The invention relates to an adjustable mold for use in continuous casting installations for producing cast strands of substantially rectangular cross section. The mold is assembled of at least two mold parts which, in order to adjust the cross section of the cast strand, are mutually shiftable transversely to the direction of extrusion.
When it is desired to change the cross section of a cast strand, in conventional continuous casting installations it is necessary to install another sliding mold of the desired size. The disadvantage of such a prior-art mold adjustment is not only the fact that a relatively large number of expensive molds, made usually of copper and provided with cooling channels, must have been kept ready for immediate use, but also the exchange required considerable installation time, resulting in relatively long down times of the entire casting installation.
An adjustable sliding mold is known from the Swiss Pat. No. 386,629, disclosing two relatively broad mold walls arranged opposite each other and engaging a pair of opposite mold parts arranged at right angles to the mold walls to complete an extrusion channel of rectangular cross section. The clearance between the mold parts is adjustable by means of spindles of an adjusting device. It has been found, however, that problems occur in prior-art molds of this kind relating to the seal between the mating surfaces of the movable and fixed mold parts. The four contact surfaces must be carefully machined with relatively great expenditures to ensure satisfactory operation of the casting device.
An improvement of this known adjustable sliding mold, relating particularly to the aforementioned sealing problem, has been devised in applicant's prior application Ser. No. 471,146, which discloses sliding molds consisting of two mutually shiftable mold parts, each having an L-shaped profile to define a rectangular channel of adjustable cross section. A particularity of this design is the provision of an arcuate guiding surface formed on the outer wall of at least one mold part, so that, in the case of casting strands of larger cross section, the conicity of the channel can be increased. This solution is applicable both to sliding molds having flat inner surfaces and for sliding molds having curved inner surfaces (circular segment molds). This prior-art solution, however, is suitable for casting a single strand only.